Real-world safety of nusinersen in Japan: results from an interim analysis of a post-marketing surveillance and safety database

Abstract

Purpose

Nusinersen is the first disease-modifying therapy to treat spinal muscular atrophy (SMA). This report describes the safety and effectiveness of nusinersen in Japanese clinical use using two data sources: an ongoing Japanese post-marketing surveillance (PMS) and the safety database of the marketing authorisation holder, Biogen .

Materials and Methods

The PMS is evaluating the safety and effectiveness of nusinersen in all patients treated with nusinersen in Japan between August 2017 and August 2025; this interim analysis included data up to May 30, 2019. Biogen safety database data up to June 30, 2019 were also included to capture adverse events (AEs) from after the interim analysis cutoff date. Collected data included medical history, dosage and administration, and AEs. Safety assessment included AEs and serious AEs (SAEs). Effectiveness analyses included motor function assessments and clinical global impressions of improvement.

Results

Of 271 patients in the PMS population, 94 had SMA type I (34.7%), and 177 had SMA types II–IV (65.3%). AEs occurred in 67 patients (24.7%) and SAEs in 23 patients (8.5%). The Biogen safety database contained reports of 345 AEs; the most common were pneumonia, headache, and pyrexia, consistent with symptoms of SMA and lumbar puncture. In the analysis set, 26.2% of patients receiving nusinersen showed motor function improvements and 99.6–100.0% showed overall improvement.

Conclusion

In this interim analysis of the PMS and Biogen safety database, nusinersen had a favourable benefit–risk profile in Japanese patients with SMA.

Keywords:

• Benefit–risk profile
• drug safety
• nusinersen
• post-marketing
• surveillance
• spinalmuscular atrophy

Acknowledgments

We would like to thank Kazutaka Ogiwara and Kimimasa Tobita who contributed to the interpretation of data and the preparation and revision of this manuscript, and Marion Barnett who wrote the first draft of this manuscript on behalf of inScience Communications, Springer Healthcare, and Sarah Greig, PhD, of inScience Communications Springer Healthcare who styled the manuscript for submission. This medical writing assistance was funded by Biogen Japan Ltd.

Disclosure statement

All authors are employees of Biogen Japan, Ltd. No other potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was funded by Biogen Japan Ltd.